1. Field
The present disclosure relates to turbomachine components, more specifically to blade outer air seals (BOAS).
2. Description of Related Art
BOAS are dynamic seals that prevent airflow from traveling around the blade tips of turbomachine blades while the turbomachine blades are spinning. BOAS are specifically designed to reduce the gap distance between the tip of the blades and the BOAS in order to prevent airflow from traveling around the blade tips.
BOAS design involves a tradeoff between an effective seal by minimizing gap distance and blade tip wear. Traditional BOAS are intentionally designed to be worn down by the blades during a break in period, which can result in the blade tips experiencing wear or damage. Also, even after break-in, differing aerodynamic, inertial, and thermal stresses can cause the blades to expand outwardly and further wear into the BOAS.
To address this, typical BOAS include an abradable coating on the thermal ceramic surface thereof to allow the blade to dig into the BOAS with reduced wear and damage. Abradable coatings add complexity and cost to the design of the BOAS. Also, abradable coatings are typically applied in a smooth fashion resulting in a smooth, strong surface which can potentially create a significant amount of blade tip wear during break-in.
Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is still a need in the art for improved BOAS. The present disclosure provides a solution for this need.